Protector



Nov. 13, 1928; 1;691,705

I w. L. (300K I PROTECTOR Filed Nov. 29, 1926 Patented Nov. 13,

UNITED STATES 1,691,705 PATENT oFFlcE.

WALLACE L. COOK, OF CHICAGO, ILLINOIS, ASSIGNOR TO RELIABLE ELECTRIC'00., OF

' CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS. i

rnorncron.

Application filed November 29, 1926. Serial No 151,422.

My invention relates to thermal protective devices adapted to beinserted in an electric circuit for breaking the circuit when anexcessive amount of current passing through a portion of the deviceheats the same above a predetermined temperature.

It is a purpose of my invention to provide a thermal protective devicehaving electrodes held in electrical engagement by heat responsivematerial with means for causing a wide separation of said electrodesupon heating said material termined temperature.

It is a further purpose of my invention to provide means whereby theelectrodes of the thermal protective device may be reset afterseparation upon softening the heat responsive means.

Another purpose of my invention is to provide an enclosing casing forthe thermal protective device and indicating meansprojecting outsidesaid casing to indicate whether the protective device is in open orclosed circuit position and to aid in resetting said device in closedposition after it has opened the circuit. 1

ther objects and advantages will appear as the description proceeds whentaken in above a predeconnection with the accompanying drawing.

However, I wish it to be understood that I do not intend to limit myselfto the exact details shown and described but that I intend to availmyself of all such modifications'as would occur to one skilled in thisart and would fall within the scope of the claim. Q

In the drawings,

Fig. 1 is a sectional view taken longitudi- Fig. 1.

why through my improved thermal protector; and

Fig. 2 is a section on the line 2-2 of Referring now in detail to thedrawings, the numeral 3 represents an elongated tubular casing which hason opposite ends thereof the terminal members 4' and 5, made of anysuitable metallic material, and which a are held on the tube 3 by meansof punched- .51-m1y'ho1d the terminals in place.

in portions such as illustratedoat 6 and 7. The tube 3 is made of aninsulating composition which is sufliciently soft to permit the portions6 and 7 to enter thereinto zlt rlld e terminal is further provided withinwardly extending portions 8 and 9 which hold the disk 10 againstoneend of the tube 3 for a purpose which will presently appear. Theterminal 5 has soldered thereto a conductor' member 11 whichextendsinwardly through an opening in the insulating disk 10 and iscoiled around the member 12 inside the tube 3. .This member 12 has the.outerlend thereof extending through the disk 10, as shown clearly inFig. 1,-and the end 14 of the conductor 11 is soldered to the end of themember 12 by means of a. comparatively hard solder which is capable ofwithstanding considerable heat. The portion of the conductor 11 that iscoiled around the member 12 serves as a heat coil adapted on the,passage of current therethrough to heat the member 12 and soften thesolder shown at 15 to permit release of the elecmember 12 inside thetube and in close proximity to the solder 15. The opening in the member12 which accommodates the solder 15 and the electrode 16 should besufiiciently large to permit the use of a considerable amount of solderso as to avoid any danger of binding between the electrodes 12 and16'when the solder is softened under heat. The electrodelfi has aportion 17 consisting of a long rod which projects lengthwise throughthetube 3 and out through the end of the terminal 4. This rod 17 serves as'an indicator to show whether or not the electrodes 12 and 16 are in.contact with each other, and serves a further purpose which willpresently appear.

Secured to the electrode 16, as at 18, is a spring member 19 whichsurrounds the rod 17 and has its free end soldered to the terminal 4 at20. This spring is adapted to be under tension when the electrodes 12and 16 are in contact. so that upon undue heating of the electrode 12due to a current flowing from terminal 5 through conductor 11, electrode12, electrode 16 spring 19 and terminal 4, the spring will serve to pullthe electrode 16 away from the electrode 12 and create a wide breakbetween the two elec-.

trodes, thus breaking the circuit in which the protector is'inserted andseparating the electrodes for enough apart to prevent any due to theaction of the spring 19 and the softening of the solder 15 the devicemay be reset by epplyine" suiiiclent heat thereto to soften thecomparatively soft solder 15 and pushing the rod 1? inwardly so as tocause the electrode-.16 to extend down into the electrode 12. The partsmay be then held in this posit-ion until the solder cools enough to holdthe electrodes 12 and 1:6 together. In some cases it might happen thatthe spring 19 would break, and this would not interfere with theresetting of the device; but, as is clearly apparent, if the member 17were not insulated from the terminal 4 the protector would beuseless,since the spring would be out of commission and there would be no meansfor creating agap by separating the members l2-and 16 when the solderwas melted by the heat. In this way it might happen that a protectorwould be reset and installed without any one becom ing aware of the factthat it could not open the circuit because the spring was broken. By useof the insulating tube 21, I make the spring 19 the only electricalconnection between electrode 16 and terminal4, so if the spring breaks,even though it is not visible from the outside, resetting of the twoelectrodes 12 and 16 will not complete the circuit between terminals 4and 5, and there I will be no danger of the tube being inserted in acircuit unless it can serve it purpose as a rotector.

From the a ove description it will be seen,

that I have provided a thermal protector wherein the solder heated bythe heat coil to release the electrodes cannot be contaminated by theinferior solder used for securing the conductors, and one wherein a wideseparation of the electrodes is obtained, to-

get-her with means for resetting and indi- I claim and desire to secureby Letters Patent. is:

A thermal protector of the character described comprising a pair ofelectrodes, heat responsive means for normally retaining said electrodesin electrical engagement and adapted upon undue increase in heat topermit separation of said electrodes, a spring normally under stressadapted to cause a wide separation of said electrodes upon softening ofsaid heat responsive means, means for again setting said electrodes intooperative position upon re-softoning of said heat responsive means, anenclosing shell housin said electrodes, heat responsive means an spring,and indicating means projecting from said shell for indicating therelative osition of said electrodes with respect to eac other.

In witness whereof, I hereunto subscribe my name' this 4th day ofNovember, A. D.,

WALLACE L. 000K.

